mpd/src/TagAny.cxx
2023-03-06 14:59:48 +01:00

152 lines
3.4 KiB
C++

// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright The Music Player Daemon Project
#include "TagAny.hxx"
#include "TagStream.hxx"
#include "TagFile.hxx"
#include "tag/Generic.hxx"
#include "song/LightSong.hxx"
#include "db/Interface.hxx"
#include "storage/StorageInterface.hxx"
#include "client/Client.hxx"
#include "protocol/Ack.hxx"
#include "fs/AllocatedPath.hxx"
#include "input/InputStream.hxx"
#include "util/Compiler.h"
#include "util/ScopeExit.hxx"
#include "util/StringCompare.hxx"
#include "util/UriExtract.hxx"
#include "LocateUri.hxx"
static void
TagScanStream(const char *uri, TagHandler &handler)
{
Mutex mutex;
auto is = InputStream::OpenReady(uri, mutex);
if (!tag_stream_scan(*is, handler))
throw ProtocolError(ACK_ERROR_NO_EXIST, "Failed to load file");
ScanGenericTags(*is, handler);
}
static void
TagScanFile(const Path path_fs, TagHandler &handler)
{
if (!ScanFileTagsNoGeneric(path_fs, handler))
throw ProtocolError(ACK_ERROR_NO_EXIST, "Failed to load file");
ScanGenericTags(path_fs, handler);
}
#ifdef ENABLE_DATABASE
/**
* Collapse "../" prefixes in a URI relative to the specified base
* URI.
*/
static std::string
ResolveUri(std::string_view base, const char *relative)
{
while (true) {
const char *rest = StringAfterPrefix(relative, "../");
if (rest == nullptr)
break;
if (base == ".")
throw ProtocolError(ACK_ERROR_NO_EXIST, "Bad real URI");
base = PathTraitsUTF8::GetParent(base);
relative = rest;
}
return PathTraitsUTF8::Build(base, relative);
}
/**
* Look up the specified song in the database and return its
* (resolved) "real" URI.
*/
static std::string
GetRealSongUri(Client &client, std::string_view uri)
{
const auto &db = client.GetDatabaseOrThrow();
const auto *song = db.GetSong(uri);
if (song == nullptr)
throw ProtocolError(ACK_ERROR_NO_EXIST, "No such song");
AtScopeExit(&db, song) { db.ReturnSong(song); };
if (song->real_uri == nullptr)
return {};
return ResolveUri(PathTraitsUTF8::GetParent(uri), song->real_uri);
}
#endif
static void
TagScanDatabase(Client &client, const char *uri, TagHandler &handler)
{
#ifdef ENABLE_DATABASE
const auto real_uri = GetRealSongUri(client, uri);
if (!real_uri.empty()) {
uri = real_uri.c_str();
// TODO: support absolute paths?
if (uri_has_scheme(uri))
return TagScanStream(uri, handler);
}
const Storage *storage = client.GetStorage();
if (storage == nullptr) {
#else
(void)client;
(void)uri;
(void)handler;
#endif
throw ProtocolError(ACK_ERROR_NO_EXIST, "No database");
#ifdef ENABLE_DATABASE
}
{
const auto path_fs = storage->MapFS(uri);
if (!path_fs.IsNull())
return TagScanFile(path_fs, handler);
}
{
const auto absolute_uri = storage->MapUTF8(uri);
if (uri_has_scheme(absolute_uri))
return TagScanStream(absolute_uri.c_str(), handler);
}
throw ProtocolError(ACK_ERROR_NO_EXIST, "No such file");
#endif
}
void
TagScanAny(Client &client, const char *uri, TagHandler &handler)
{
const auto located_uri = LocateUri(UriPluginKind::INPUT, uri, &client
#ifdef ENABLE_DATABASE
, nullptr
#endif
);
switch (located_uri.type) {
case LocatedUri::Type::ABSOLUTE:
return TagScanStream(located_uri.canonical_uri, handler);
case LocatedUri::Type::RELATIVE:
return TagScanDatabase(client, located_uri.canonical_uri,
handler);
case LocatedUri::Type::PATH:
return TagScanFile(located_uri.path, handler);
}
gcc_unreachable();
}